[bojan]

Barlow (it will significantly extend the focal plane plane away from the tube) is better than eyepiece projection (lower distortions and better resolution, good for planets and Moon).. but neither is good for nebulae and extended objects (due to high effective F-number of the system).
However, you will have to get the low-profile focuser if you want to use prime focus directly (or with field flattener).
You can try to make it yourself (or with help of someone who has a lathe), it is really not a rocket science.